Upfront haploidentical transplant for acquired severe aplastic anemia: registry-based comparison with matched related transplant

Treatment of relapsed/refractory severe aplastic anemia in children: Evidence-based recommendations

Severe aplastic anemia (SAA) is a rare potentially fatal hematologic disorder. Although overall outcomes with treatment are excellent, there are variations in management approach, including differences in treatment between adult and pediatric patients. Certain aspects of treatment are under active investigation in clinical trials. Because of the rarity of the disease, some pediatric hematologists may have relatively limited experience with the complex management of SAA. The following recommendations reflect an up-to-date evidence-based approach to the treatment of children with relapsed or refractory SAA.

Alternative donor transplantation for severe aplastic anemia: a comparative study of the SAAWP EBMT

ABSTRACT

Selecting the most suitable alternative donor becomes challenging in severe aplastic anemia (SAA) when a matched sibling donor (MSD) is unavailable. We compared outcomes in patients with SAA undergoing stem cell transplantation (SCT) from matched unrelated donors (MUD) (n = 1106), mismatched unrelated donors (MMUD) (n = 340), and haploidentical donors (Haplo) (n = 206) registered in the European Society for Blood and Marrow Transplantation database (2012-2021). For Haplo SCT, only those receiving posttransplant cyclophosphamide for graft-versus-host disease (GVHD) prophylaxis were included. Median age was 20 years, and the median time from diagnosis to transplantation 8.7 months. Compared with MUD, MMUD (hazard ratio [HR], 2.93; 95% confidence interval [CI], 1.52-5.6) and Haplo (HR, 5.15; 95% CI, 2.5-10.58) showed significantly higher risks of primary graft failure. MUD had lower rates of acute GVHD compared with MMUD and Haplo (grade 2-4: 13%, 22%, and 19%, respectively; P < .001; grade 3-4: 5%, 9%, and 7%, respectively; P = .028). The 3-year nonrelapse mortality rate was 14% for MUD, 19% for MMUD, and 27% for Haplo (P < .001), whereas overall survival and GVHD and relapse-free survival (GRFS) rates were 81% and 73% for MUD, 74% and 65% for MMUD, and 63% and 54% for Haplo, respectively (P < .001). In addition to donor type, multivariable analysis identified other factors associated with GRFS such as patient age, performance status, and interval between diagnosis and transplantation. For patients with SAA lacking an MSD, our findings support MUDs as the preferable alternative donor option. However, selecting between an MMUD and Haplo donor remains uncertain and requires further exploration.

Addition of ruxolitinib to standard graft-versus-host disease prophylaxis for allogeneic stem cell transplantation in aplastic anemia patients

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) offers rapid hematopoietic and immune reconstitution for aplastic anemia (AA). As a non-malignant disorder, attenuation of GVHD remains a clinical priority in AA patients. Our study sought to investigate the safety and efficacy of the prophylactic use of ruxolitinib in allogeneic HSCT. A total of 35 AA patients were retrospectively consecutively treated with allo-HSCT whereby ruxolitinib was added to the standard GVHD prophylaxis regimen (rux group). The addition of peri-transplant ruxolitinib did not impact the engraftment and graft function, while better recovery of CD4+ Tregs in the rux group was observed. Interestingly, the rux group demonstrated significantly lower incidence of bacterial/fungal infections (17.14% vs 45.71%). Compared to the control group, the rux group exhibited significantly lower incidence of moderate to severe aGVHD (17.1% vs 48.6%) with a trend toward lower severe aGVHD (8.6% vs 20%) and cGVHD (26.2 vs 38.3). The rux group also demonstrated a trend toward higher GVHD and failure-free survival (GFFS: 85.7% vs 68.6%) and lower TRM (2.9% vs 14.3%). Addition of ruxolitinib to standard GVHD prophylaxis regimen, thus, represents a safe and highly efficient method for the attenuation of GVHD with better outcome of allo-HSCT.

Breaking barriers: supporting hematopoietic stem cell transplant program through collaborative radiation therapy service from a physically distant center

BACKGROUND

Total body irradiation (TBI) for hematopoietic stem cell transplant (HSCT) has certain distinct advantages, such as uniform dose distribution and lack of drug resistance, but it is not widely available in resource-constrained settings. To overcome the limitations of in-house radiotherapy services in hematology centers, we evaluated the feasibility of conducting HSCT programs in coordination with two physically distant centers using a reduced-intensity TBI protocol.

METHODS

Thirty-two patients with a median age of 20.5 years were included in the study. Fifteen patients were diagnosed with aplastic anemia, 10 patients with acute myeloid leukemia (AML), 3 patients with acute lymphocytic leukemia (ALL), and 4 patients with other hematological conditions. Conditioning regimens used were fludarabine plus cyclophosphamide in 29 cases, fludarabine-cytarabine ATG in 2 cases, and busulfan plus fludarabine in 1 case. The TBI dose was 3 Gy in 28 cases and 2 Gy in 4 cases. Patients were followed monthly after TBI, and the major toxicities were recorded.

RESULTS

The median follow-up was 22 months. The most common acute complication was acute graft-versus-host disease (GVHD), which occurred in 15.6% of patients. The major late complications were chronic GVHD (9.3%), Cytomegalovirus (CMV) infection (34.3%), and CMV-induced secondary graft failure (6.2%). Seventy-five percent of patients were alive, 21.9% were dead, and 1 patient was lost to follow-up.

CONCLUSIONS

HSCT based on TBI is feasible even if the center lacks a radiotherapy facility by coordinating with a remote radiotherapy facility. without compromising the patient's outcome.

Recombinant Human Thrombopoietin Promotes Platelet Engraftment in Severe Aplastic Anemia Patients Following Treatment With Haploid Hematopoietic Stem Cell Transplantation using Modified Post-Transplantation Cyclophosphamide

BACKGROUND

Recombinant human TPO (rhTPO) promotes platelet engraftment in patients after allogeneic HSCT (allo-HSCT). However, the effects of rhTPO on platelet recovery after Haplo-HSCT in patients with severe aplastic anemia (SAA) have not been intensively studied.

OBJECTIVE

We aimed to evaluate the efficacy of rhTPO on platelet engraftment in patients with SAA who were treated with Haplo-HSCT using post-transplantation cyclophosphamide (PTCy).

STUDY DESIGN

SAA patients who received Haplo-HSCT plus PTCy regimen were divided into the rhTPO group (with subcutaneous injection of rhTPO, n = 28) and Control group (no rhTPO administration, n = 27). The engraftment of platelet/neutrophil, platelet infusion amount, and transplant-related complications between the 2 groups were compared.

RESULTS

All 55 patients showed successful hematopoietic reconstitution. The median time of platelet engraftment was 11 (9 to 29) days in the rhTPO group and 14 (9 to 28) days in the Control group (P = .003). The rhTPO group had a significantly reduced amount of infused platelets compared to the Control group (2 (1 to 11.5) versus 3 (1 to 14) therapeutic doses; P = .004). There was no significant difference between the 2 groups regarding median time of neutrophil engraftment, incidence of acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD), incidence of cytomegalovirus or Epstein-Barr virus reactivation, 3-yr overall survival rate, and failure-free-survival rate. No obvious adverse reactions were observed in the rhTPO group.

CONCLUSION

rhTPO promoted platelet engraftment, reduced the amount of transfused platelets, and demonstrated good safety profiles without evidence of adverse reactions in patients with SAA who received Haplo-HSCT using PTCy regimen.

Haploidentical hematopoietic stem cell transplantation as a first-line treatment for paediatric severe aplastic anemia: a single-center research

MRD-HSCT is the first-line therapy for children with SAA, while it is not easy to find a compatible donor due to the Chinese one-child policy. IST has a high recurrence rate, a risk of clonal transformation. Thus, Haplo-HSCT, as a first-line treatment, has gradually attracted clinicians' attention. To evaluate the efficacy of Haplo-HSCT in children with SAA, we performed a retrospective study (2006.06-2021.01) of 210 patients with AA who received HSCT or IST in Beijing Children's Hospital. The OS and FFS rates were analyzed to evaluate the efficacy of Haplo-HSCT and IST. We found that from 2006 to 2021, 3- and 5-year cumulative survival rates were both 85.3% in the first-line Haplo group, 98.1% and 96.8% in the first-line IST group, both 85.7% in the ATG group (P = 0.866), both 100% in the ATG + TPO group (P = 0.016), and 99.1% and 97.2% in the ATG + eltrombopag group (P = 0.056). 3- and 5-year cumulative FFS rates were both 85.3% in the first-line Haplo-HSCT group and 67.5% and 66.2% in the first-line IST group (P = 0.033). Therefore, we believe that Haplo-HSCT can be a first-line treatment for paediatric SAA.

The state of the art in the treatment of severe aplastic anemia: immunotherapy and hematopoietic cell transplantation in children and adults

Acquired aplastic anemia (AA) is an immune-mediated bone marrow (BM) failure where marrow disruption is driven by a cytotoxic T-cell-mediated autoimmune attack against hematopoietic stem cells. The key diagnostic challenge in children, but also in adults, is to exclude the possible underlying congenital condition and myelodysplasia. The choice of treatment options, either allogeneic hematopoietic cell transplantation (alloHCT) or immunosuppressive therapy (IST), depends on the patient's age, comorbidities, and access to a suitable donor and effective therapeutic agents. Since 2022, horse antithymocyte globulin (hATG) has been available again in Europe and is recommended for IST as a more effective option than rabbit ATG. Therefore, an update on immunosuppressive strategies is warranted. Despite an improved response to the new immunosuppression protocols with hATG and eltrombopag, some patients are not cured or remain at risk of aplasia relapse or clonal evolution and require postponed alloHCT. The transplantation field has evolved, becoming safer and more accessible. Upfront alloHCT from unrelated donors is becoming a tempting option. With the use of posttransplant cyclophosphamide, haploidentical HCT offers promising outcomes also in AA. In this paper, we present the state of the art in the management of severe AA for pediatric and adult patients based on the available guidelines and recently published studies.

Upfront Umbilical Cord Blood Transplantation Versus Immunosuppressive Therapy for Pediatric Patients With Idiopathic Severe Aplastic Anemia

Umbilical cord blood transplantation (UCBT) has been rarely reported as a first-line treatment for idiopathic severe aplastic anemia (SAA) patients lacking HLA-matched sibling donors (MSD). Our study aimed to compare the clinical outcomes of pediatric SAA patients who received UCBT and immunosuppressive therapy (IST) upfront. A retrospective analysis was performed on 43 consecutive patients who received frontline IST (n = 17) or UCBT (n = 26) between July 2017 and April 2022. The 3-year overall survival (OS) was comparable between the UCBT and IST groups (96.2% versus 100%, P = .419), while the 3-year event-free survival (EFS) was significantly better in the former than in the latter (88.5% versus 58.8%, P = .048). In the UCBT group, 24 patients achieved successful engraftment, 2 patients developed severe acute graft-versus-host disease (aGVHD), no extensive chronic GVHD (cGVHD), and a high GVHD-free, failure-free survival (GFFS) of 84.6% at 3 years. After 1 year of treatment, 12 patients in the IST group responded, while 5 patients did not achieve remission and 2 patients had disease relapse. At both 3 and 6 months after treatment, the proportion of transfusion-independent patients was higher in the UCBT group than in the IST group. Faster immune recovery and earlier transfusion independence further reduced the risk of infection and bleeding, thereby improving health-related quality of life in the UCBT-treated group. Our results suggested that UCBT as upfront therapy may be an effective and safe option for pediatric SAA patients, with favorable outcomes in experienced centers.

Letermovir Effectively Prevents Cytomegalovirus Infection in Patients with Aplastic Anemia After Hematopoietic Stem Cell Transplantation: A Real-World Retrospective Cohort Study

INTRODUCTION

In this single-center retrospective cohort study, we investigated the efficacy of letermovir in preventing Cytomegalovirus (CMV) infection in patients with aplastic anemia (AA) who have undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS

Based on whether or not letermovir was used for preventing CMV infection, the patients were categorized into two groups: letermovir and control groups. The overall survival (OS) rate and cumulative incidence of CMV infection during the first 100 days after allo-HSCT were evaluated. The study included 21 matched pairs of patients, identified through propensity score matching analysis, to compare CMV infection rates, treatment efficacy, and regression.

RESULTS

The incidence of CMV infection within 100 days after transplantation was significantly lower in the letermovir group than in the control group (26.5 vs. 77.4%, respectively; P < 0.001), among a total of 87 patients who underwent the transplant. In the matched cohort of 21 patients with AA, the letermovir group also showed a significantly reduced cumulative incidence of CMV infection (14.3 vs. 90.5% in the control group; P < 0.001). Compared to the control group, patients with CMV infection in the letermovir group had lower CMV-DNA load and a shorter clearance time. However, there was no significant difference in OS between both groups (P = 0.34).

CONCLUSIONS

Letermovir effectively prevents CMV infection in allo-HSCT recipients with AA and demonstrates a high safety profile.

Pediatric Bone Marrow Failure: A Broad Landscape in Need of Personalized Management

Irreversible severe bone marrow failure (BMF) is a life-threatening condition in pediatric patients. Most important causes are inherited bone marrow failure syndromes (IBMFSs) and (pre)malignant diseases, such as myelodysplastic syndrome (MDS) and (idiopathic) aplastic anemia (AA). Timely treatment is essential to prevent infections and bleeding complications and increase overall survival (OS). Allogeneic hematopoietic stem cell transplantation (HSCT) provides a cure for most types of BMF but cannot restore non-hematological defects. When using a matched sibling donor (MSD) or a matched unrelated donor (MUD), the OS after HSCT ranges between 60 and 90%. Due to the introduction of post-transplantation cyclophosphamide (PT-Cy) to prevent graft versus host disease (GVHD), alternative donor HSCT can reach similar survival rates. Although HSCT can restore ineffective hematopoiesis, it is not always used as a first-line therapy due to the severe risks associated with HSCT. Therefore, depending on the underlying cause, other treatment options might be preferred. Finally, for IBMFSs with an identified genetic etiology, gene therapy might provide a novel treatment strategy as it could bypass certain limitations of HSCT. However, gene therapy for most IBMFSs is still in its infancy. This review summarizes current clinical practices for pediatric BMF, including HSCT as well as other disease-specific treatment options.

Combining PTCy and ATG for GvHD prophylaxis in non-malignant diseases

Bone marrow transplantation for non-malignant diseases such as aplastic anemia and hemoglobinopathies is a burgeoning clinical area. The goal of these transplants is to correct the hematopoietic defect with as little toxicity as possible. This requires mitigation of transplant-specific toxicities such as graft versus host disease, given this is not needed in non-malignant disorders. This review details current clinical outcomes in the field with a focus on post-transplantation cyclophosphamide and anti-thymoglobulin as intensive graft versus host disease prophylaxis to achieve that goal.

Haploidentical transplants with a G-CSF/ATG-based protocol: Experience from China

Haploidentical donor stem cell transplantation (haplo-SCT) has made great advances in recent decades. The granulocyte colony-stimulating factor (G-CSF)- and antithymocyte globulin (ATG)-based protocol, which is known as the Beijing Protocol, represents one of the current T-cell repletion strategies in haplo-SCT. The key elements of the Beijing Protocol for graft versus host disease (GvHD) prophylaxis include G-CSF inducing T-cell tolerance and altering graft cell components, as well as ATG administration exerting an immunoregulatory effect for intensive prophylaxis. This review will summarize the GvHD incidence, the underlying novel mechanism for GvHD prophylaxis, how to optimize GvHD prophylaxis, and the recent advances of the Beijing Protocol, mainly focusing on the issues of GvHD.

Time-dependent analysis of the impact on early cytomegalovirus reactivation of HLA mismatch and acute graft-versus-host disease after allogeneic hematopoietic cell transplantation from related donors in acquired aplastic anemia

Cytomegalovirus (CMV) reactivation is an important issue in allogeneic hematopoietic cell transplantation (HCT). The incidence of early CMV reactivation is notably high in HLA-mismatched HCT. However, the interactions between HLA mismatch and acute graft-versus-host disease (aGvHD), a time-dependent event, make it methodologically challenging to evaluate the independent impact on CMV reactivation of the two variables. We retrospectively analyzed 355 patients with acquired aplastic anemia who received related donor transplants using a unified antithymocyte globulin-based platform. Patients were divided into group 1 (6/6 HLA match), group 2 (1-2/6 HLA allelic mismatch), and group 3 (3/6 HLA allelic mismatch). The impact of covariates was analyzed through two models: (1) time-dependent Cox and (2) dynamic landmarking analysis. The time-dependent Cox model showed that the HLA mismatch of 3/6 alleles (hazard ratio (HR) =1.852, P = .004) and aGvHD (HR = 1.009, P = .019) were independent risk factors for CMV reactivation. With the dynamic landmarking analysis, a higher HLA disparity correlated to increased early CMV reactivation (HR = 1.606, P = .001) at all time points. Developing aGvHD following HCT was generally associated with a higher incidence of CMV reactivation (HR = 1.623, P = .013), though its impact decreased with successive later landmark time points. In conclusion, our data suggest that the higher HLA disparity and aGvHD increases susceptibility to early CMV reactivation. In particular, the dynamic landmarking analysis demonstrated the time-varying effect of aGvHD on CMV reactivation, and HLA mismatch showed a profound impact over time following HCT.

Meta-analysis of the results of haploidentical transplantation in the treatment of aplastic anemia

This meta-analysis was to evaluate the outcome of haploidentical hematopoietic stem cell transplantation (Haplo-HSCT) for aplastic anemia (AA) compared with matched related donor (MRD)-HSCT, matched unrelated donor (MUD)-HSCT, and immunosuppressive therapy (IST). Pubmed, Embase, Cochrane Library, Web of Science, CNKI, WanFang, and VIP databases were searched for relevant studies from inception to 22 June 2022. Relative risk (RR) was used to indicate the effect indicator, with a 95% confidence interval (CI) being applied to express the effect size. A subgroup analysis based on the literature quality (low, fair, and high) was applied. Totally, 25 studies were included in this study, comprising 2252 patients. Our findings demonstrated no difference between Haplo-HSCT and MRD-HSCT in 1-, 2-, and 3-year overall survival (OS), failure-free survival (FFS), and engraftment. However, Haplo-HSCT had higher incidences of II-IV acute graft-versus-host disease (aGVHD), chronic GVHD (cGVHD), and cytomegalovirus infection. There were no differences in 3- and 5-year OS, 3-year FFS, platelet engraftment, graft failure (GF), II-IV grade of aGVHD, and complication between Haplo-HSCT and MUD-HSCT; however, Haplo-HSCT had a lower incidence of cGVHD. Compared with IST, Haplo-HSCT had a higher 3-year FFS and 3- and 6-month response rate. However, there were no differences in 3- and 5-year OS, and 12-month response rate between Haplo-HSCT and IST. This study suggests that Haplo-HSCT may be a realistic therapeutic option for AA, which may provide a reference for decision-making.

Graft-versus-host disease and relapse/rejection-free survival after allogeneic transplantation for idiopathic severe aplastic anemia: a comprehensive analysis from the SAAWP of the EBMT

Survival after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for severe idiopathic aplastic anemia (SAA) has improved in recent years, approaching 75% at 5 years. However, an SAA-adapted composite endpoint, graft-versus-host disease (GvHD) and relapse/rejection-free survival (GRFS), may more accurately assess patient outcomes beyond survival. We analyzed GRFS to identify risk factors and specific causes of GRFS failure. Our retrospective analysis from the Severe Aplastic Anemia Working Party of the European Society for Blood and Marrow Transplantation included 479 patients with idiopathic SAA who underwent allo-HSCT in two conventional situations: i) upfront allo-HSCT from a matched related donor (MRD) (upfront cohort), and ii) allo-HSCT for relapsed or refractory SAA (rel/ref cohort). Relevant events for GRFS calculation included graft failure, grade 3-4 acute GvHD, extensive chronic GvHD, and death. In the upfront cohort (n=209), 5-year GRFS was 77%. Late allo-HSCT (i.e., >6 months after SAA diagnosis) was the main poor prognostic factor, specifically increasing the risk of death as the cause of GRFS failure (hazard ratio [HR]=4.08; 95% confidence interval [CI]: 1.41-11.83; P=0.010). In the rel/ref cohort (n=270), 5-year GRFS was 61%. Age was the main factor significantly increasing the risk of death (HR=1.04; 95% CI: 1.02-1.06; P<0.001), acute GvHD (HR=1.03; 95% CI: 1.00-1.07; P=0.041), and chronic GvHD (HR=1.04; 95% CI: 1.01-1.08; P=0.032) as the cause of GRFS failure. GRFS after upfront MRD allo-HSCT was very good, notably with early allo-HSCT, confirming that younger patients with an MRD should be transplanted immediately. GRFS was worse in cases of salvage allo-HSCT, most notably in older patients, questioning the utility of allo-HSCT earlier in the disease course.

Prognostic Impact of Quantifying Sarcopenia and Adipopenia by Chest CT in Severe Aplastic Anemia Patients Treated With Allogeneic Hematopoietic Stem Cell Transplantation

RATIONALE AND OBJECTIVES

To investigate the prognostic role of chest CT-defined sarcopenia and adipopenia in severe aplastic anemia (SAA) patients treated with hematopoietic stem cell transplantation (HSCT).

MATERIALS AND METHODS

This was a retrospective study of 123 consecutive SAA patients treated with HSCT. CT imaging was performed to quantify the pectoralis muscle (including major and minor) index (PMI) and the corresponding subcutaneous adipose tissue index (SAI). Sarcopenia and adipopenia were defined as PMI and SAI lower than the respective sex-specific medians. Correlations of the PMI and SAI with anthropometric indexes were calculated. Transplant-related outcomes were compared between the sarcopenia and adipopenia groups. Prognostic factors for overall survival (OS) and fail-free survival (FFS) were identified by Cox regression and were used to create a nomogram. The accuracy of the nomogram was evaluated by ROC curves.

RESULTS

PMI showed good correlation with BMI and fat-free mass index (p < 0.001). SAI correlated with BMI and fat mass index (p < 0.001). The sarcopenia group (47.2%) had a significantly worse 3-year OS (90.8% vs. 77.6%, p = 0.045) and 3-year FFS (89.2% vs. 74.1%, p = 0.035) than the nonsarcopenia group. Sarcopenia status and diagnostic category were used to construct the nomogram of OS, as these were independent prognostic factors in the multivariate analysis for OS and FFS (p < 0.05). The area under the curve of the nomogram at one year and three years was 0.801 and 0.721, respectively.

CONCLUSION

Sarcopenia indicates a poor prognosis in SAA patients undergoing HSCT. Intensive supportive care is suggested for SAA patients with sarcopenia before transplantation.

Busulfan for Allogeneic Hematopoietic Stem Cell Transplantation in Children with Severe Aplastic Anemia: A Retrospective Study

INTRODUCTION

This retrospective study aimed to compare a range of conditioning regimens in children with severe aplastic anemia (SAA) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) at the Seventh Medical Center of PLA General Hospital between January 2008 and June 2017.

METHODS

Patients were categorized into the Bu (Bu + Flu + Cy + ATG-F regimen) and control (Flu + Cy + ATG-F) groups, with a median follow-up time after HSCT of 3.5 (range, 3.1-6.2) and 3.7 (3.2-5.9) years in the Bu and control groups, respectively.

RESULTS

No differences were observed between the two groups regarding the median time of peripheral blood neutrophil and platelet engraftment (p = 0.538 and p = 0.491); the 28-day engraftment rates of neutrophils were similar (p = 0.199), although higher for platelets with Bu (p = 0.044). Additionally, graft failure was 0% and 20.0% in the Bu and control groups, respectively (p = 0.004). In both groups, the incidence of grades III-IV (or grades II-IV) acute graft-versus-host disease (GVHD) and chronic GVHD was not significantly different (p > 0.05). Moreover, the 3-year overall survival and failure-free survival did not show significant differences (p = 0.670 and p = 0.908).

DISCUSSION

In children with SAA undergoing allo-HSCT, conditioning regimen with Bu + Flu + Cy + ATG-F is capable of enhancing the myeloablation effect, promoting donor hematopoietic stem cell engraftment, and reducing the graft failure rate. Furthermore, it does not increase the incidence of complications, including GVHD.

Influence of SPIO labelling on the function of BMSCs in chemokine receptors expression and chemotaxis

Bone marrow-derived mesenchymal stem cells (BMSCs) are increasingly being used in bone marrow transplantation (BMT) to enable homing of the allogeneic hematopoietic stem cells and suppress acute graft versus host disease (aGVHD). The aim of this study was to optimize the labelling of BMSCs with superparamagnetic iron oxide particles (SPIOs), and evaluate the impact of the SPIOs on the biological characteristics, gene expression profile and chemotaxis function of the BMSCs. The viability and proliferation rates of the SPIO-labeled BMSCs were analyzed by trypan blue staining and CCK-8 assay respectively, and the chemotaxis function was evaluated by the transwell assay. The expression levels of chemokine receptors were measured by RT-PCR and flow cytometry. The SPIOs had no effect on the viability of the BMSCs regardless of the labelling concentration and culture duration. The labelling rate of the cells was higher when cultured for 48 h with the SPIOs. Furthermore, cells labeled with 25 µg/ml SPIOs for 48 h had the highest proliferation rates, along with increased expression of chemokine receptor genes and proteins. However, there was no significant difference between the chemotaxis function of the labeled and unlabeled BMSCs. To summarize, labelling BMSCs with 25 µg/ml SPIOs for 48h did not affect their biological characteristics and chemotaxis function, which can be of significance for in vivo applications.

Comparison of haploidentical-allogeneic hematopoietic stem cell transplantation and intensive immunosuppressive therapy for patients with severe aplastic anemia with an absolute neutrophil count of zero: a retrospective study

A retrospective analysis was conducted based on the clinical data from 60 patients older than 16 years from January 2016 to January 2021. All the patients were newly diagnosed with severe aplastic anemia (SAA) with an absolute neutrophil count (ANC) of zero. We compared the hematological response and survival of haploidentical-allogeneic hematopoietic stem cell transplantation (HID-HSCT) (n = 25) and intensive immunosuppressive therapy (IST) (n = 35) treatments. At six months, the overall response rate and complete response were significantly higher in the HID-HSCT group than those in the IST group (84.0% vs. 40.0%, P = 0.001; 80.0% vs. 17.1%, P = 0.001). With a median follow-up of 18.5 months (4.3~30.8 months), patients in the HID-HSCT group had longer overall survival and event-free survival (80.0% vs. 47.9%, P = 0.0419; 79.2% vs. 33.5%, P = 0.0048). These data suggested that HID-HSCT might be an effective alternative treatment option for adult patients with SAA with an ANC of zero, which requires further validation in an additional prospective study.

Low-dose post-transplant cyclophosphamide with G-CSF/ATG based haploidentical protocol provides favorable outcomes for SAA patients

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT), as one of the life-saving treatments for severe aplastic anemia (SAA), is widely used because of its great donor availability. Over decades, granulocyte colony-stimulating factor (G-CSF)/antithymocyte globulin (ATG)-based protocol (the so-called Beijing Protocol) has achieved favorable engraftment and survival outcomes. In this study, we modified the conventional Beijing Protocol: the full-dose Cyclophosphamide (Cy) (200 mg/kg in total) was divided into 42.75 mg/kg Cy on day -5 to day -2 and Low dose post-transplant Cy (PTCy) (14.5 mg/kg on days +3 and +4), hoping to reduce the incidence of severe acute graft-versus-host disease (aGVHD) and to guarantee successful and stable engraftment. Here we retrospectively reported and analyzed the data of first 17 patients with SAA who had received haplo-HSCT using this novel regimen between August 2020 and August 2022. The median follow-up was 522 days (range, 138-859 days). No patient developed primary graft failure. Four (23.5%) patients developed grade II bladder toxicity, two (11.8%) patients developed grade II cardiotoxicity. All patients achieved neutrophil and platelet engraftment at median times of 12 days (range, 11-20 days) and14 days (range, 8-36 days). During our follow-up, no patients developed grade III-IV aGVHD. The cumulative incidence of grade II and grade I aGVHD at 100 days was 23.5% (95% CI, 6.8%-49.9%) and 47.1% (95% CI, 23.0%-72.2%). Three patients (17.6%) developed chronic GVHD of skin, mouth, and eyes and all of which were mild. All patients are alive by the end of the follow-up, with a failure-free survival of 100%, which was defined as survival without treatment failures, such as death, graft failure, or relapse rate. The rate of cytomegalovirus (CMV) reactivation was 82.4% (95% CI, 64.3%-100%). The rate of Epstein-Barr virus (EBV) reactivation was 17.6% (95% CI, 3.8%-43.4%). No CMV disease and post-transplantation lymphoproliferative disorder (PTLD) occurred among these patients. In conclusion, the encouraging results of prolonged survival outcomes and reduced incidence of GVHD suggest promising effect of this novel regimen in haplo-HSCT for patients with SAA. Larger-sample prospective clinical trials are needed to confirm the effectiveness of this regimen.

Prospective study of a modified posttransplant cyclophosphamide regimen for severe aplastic anemia patients with HLA-haploidentical transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative modality for severe aplastic anemia (SAA). The availability of haploidentical donors has expanded valid choices for SAA. However, previous posttransplantation cyclophosphamide (PTCy)-based protocols for HLA-haploidentical HSCT in SAA patients are associated with relatively delayed neutrophil and platelet engraftment. We prospectively studied HLA-haploidentical HSCT using bone marrow combined with peripheral blood stem cells as grafts and a modified PTCy regimen for treating SAA; we evaluated the efficacy and safety of this regimen, which had an increased dose (from 4.5 mg/kg to 6.0 mg/kg) and backward adjusted timing (from day -9 to -7 to day -5 to -3) of antithymocyte globulin (ATG) compared with previous PTCy protocols. Seventy-one eligible patients were included in this prospective study between July 2019 and June 2022. The median time to and cumulative incidence (CI) of neutrophil and platelet engraftment were 13 days (range, 11-19) and 97.2±2.2% and 12 days (range, 7-62) and 94.4 ± 2.9%, respectively. Five patients experienced graft failure (GF), including 2 with primary GF and 3 with secondary GF. The CI of GF was 7.0±3.1%. The interval between diagnosis and transplantation (≥1 year) was a risk factor for GF development (HR 8.40, 95% confidence interval (1.40-50.47), p=0.02). No patients developed grade IV acute graft-versus-host disease (aGVHD) or severe chronic GVHD (cGVHD). The 100-day CI of grade II-IV aGVHD and 2-year cGVHD were 13.4±4.2% and 5.9±2.9%, respectively. With a median follow-up of 580 days (range, 108-1014) for 63 survivors, the estimated 2-year overall survival (OS) and 2-year GVHD-free and failure-free survival (GFFS) were 87.3% (95% confidence interval, 79.4-96.0) and 83.8% (95% confidence interval, 74.9-93.7), respectively. In conclusion, the PTCy regimen with an increased dose and backward adjusted timing of ATG is an effective and feasible choice for treatment with HLA-haploidentical HSCT using BM combined with PBSCs as grafts, with a high rate of and faster engraftment, a low rate and intensity of aGVHD and cGVHD, and prolonged OS and GFFS.

Comparison of hematopoietic stem cell transplantation and immunosuppressive therapy as the first-line treatment option for patients with severe hepatitis−associated aplastic anemia

Hepatitis-associated aplastic anemia (HAAA) is a rare variant of acquired aplastic anemia characterized with a syndrome of bone marrow failure after hepatitis. We retrospectively analyzed the outcomes of consecutive severe HAAA patients who received immunosuppressive therapy (IST, n = 70), matched-sibling donor hematopoietic stem cell transplantation (MSD-HSCT, n = 26) or haploidentical-donor (HID) HSCT (n = 11) as the first-line treatment. In the IST group, the hematologic response (HR) rate was 55.71% at 6 months. In contrast, HSCT recipients exhibited significantly more rapid and sustained hematopoiesis (HR 76.92%, 96.15% and 96.15% at 3, 6 and 12months, respectively). The 5-year overall survival (OS) was not different among IST (83.7 ± 4.9%), MSD-HSCT (93.3 ± 6.4%) and HID-HSCT group (80.8 ± 12.3%). Compared with IST, MSD and HID-HSCT demonstrated a trend of superiority in the estimated 5-year failure-free survival rates (93.3 ± 6.4% vs 64.3 ± 6.0%, p = 0.05; 80.8 ± 12.3% vs 64.3 ± 6.0%, p = 0.57). In subsequent stratified analysis on age, we found that HID-HSCT showed its efficacy and safety among young patients. In sum, MSD-HSCT remains first-line treatment choice for HAAA, whereas HID-HSCT represents an alternative treatment choice in addition to IST for young patients (&lt; 40 years) without a matched sibling donor.

[Clinical analysis of 76 patients with severe aplastic anemia treated with haploid hematopoietic stem cell transplantation]

Objective: The purpose of this study is to determine the efficacy of haploidentical donor hematopoietic stem cell transplantation in the treatment of severe aplastic anemia. Methods: The clinical data of 76 patients with severe aplastic anemia (SAA) patients who underwent haplo-HSCT from December 2014 to October 2020 were selectively analyzed. There were 50 males and 26 females with a median age of 16 (3-52) years old. There were 49 SAA-Ⅰ patients, 18 SAA-Ⅱ patients, and 9 patients with hepatitis-associated aplastic anemia. There were 15 cases of bone marrow put together with peripheral blood stem cell transplantation and 61 cases of peripheral blood stem-cell transplantation. Conditioning regimens were Cyclophosphamide (CY) + Fludarabine (Flu) + ATG for 46 patients and Busulfan (Bu) + CY+Flu+ATG for 30 patients. Results: Three patients died during the myelosuppressive phase following transplantation, and 73 patients had a median time of neutrophil engraftment of 12 (9-21) days; in addition to 3 patients who died early, 8 patients did not obtain platelet reconstruction after transplantation, and 65 patients had platelet engraftment with a medium time of 14 (9-90) d. The incidence of primary graft failure was 10.9% and the incidence of secondary graft failure was 5.5%. The incidence of Ⅱ-Ⅳ acute graft-versus-host disease (aGVHD) was 38.4%, the incidence of Ⅲ-Ⅳ aGVHD was 16.4%, the incidence of chronic graft anti-host disease (cGVHD) was 35.8%, and the incidence of extensive cGVHD was 22.4%. The medium follow-up time was 19.5 (1-75) months, the prospective overall survival (OS) for 2 years was (78.6±5.0) %, the failure-free survival (FFS) was (75.9±5.1) %, and the transplant-related mortality was (20.2±4.9) %. Multi-factor analysis revealed that the patient older than 35 years old, Ⅲ/Ⅳ aGVHD, HCT-CI≥3, the pre-transplant ferritin ≥1 500 μg/L, the number of neutrophils >1×10(9)/L at the time of onset were risk factors affecting OS (P=0.008, 0.008, 0.014, 0.004, 0.027) . Patients with graft failure had lower OS and FFS than other patients (P<0.001) . Conclusion: Haplo-HSCT is an effective method for treating SAA in children, adolescents, and young patients, and the occurrence of severe aGVHD and severe infection, as well as graft failure, are the main causes of survival rate. The prevention and treatment of severe aGVHD and infection are essential to improve efficacy.

Impact of Conditioning Regimen and Graft-versus-Host Disease Prophylaxis on The Outcome of Haploidentical Peripheral Blood Stem Cell Transplantation for High-Risk Severe Aplastic Anemia in Children and Young Adults: A Report from the Pediatric Severe Aplastic Anemia Consortium of India

Allogenic hematopoietic cell transplantation (HCT) is the best curative approach for patients with severe aplastic anemia (SAA). The outcomes of HCT from haploidentical family donors (HFDs) have improved, making it a feasible option for patients lacking an HLA-identical donor. However, data on HFD-HCT for younger patients with SAA is sparse. In this multicenter retrospective study, we evaluated the outcomes of 79 patients undergoing HFD-HCT for SAA. All the patients were heavily pretransfused, the median time to HCT was >12 months, and 67% had failed previous therapies. Conditioning was based on fludarabine (Flu)-cyclophosphamide (Cy)-antithymocyte globulin (ATG)/total body irradiation (TBI) with or without thiotepa/melphalan (TT/Mel). Post-transplantation Cy (PTCy) and calcineurin inhibitors (CNIs)/sirolimus were used as graft-versus-host disease (GVHD) prophylaxis with or without abatacept. The rate of primary graft failure (PGF) was 16.43% overall, lower in patients conditioned with TT/Mel. The incidences of acute and chronic GVHD were 26.4% and 18.9%, respectively. At a median follow-up of 48 months, the overall survival (OS) and event-free survival (EFS) were 61.6% and 58.1%, respectively. Both OS and EFS were better in the TT/Mel recipients and with abatacept as GVHD prophylaxis. On multivariate analysis, the use of abatacept was found to favorably impact the outcome variables, including GVHD and EFS. Our study suggests that PTCy-based HFD-HCT is a reasonable option for young patients with high-risk SAA, in whom optimization of conditioning and GVHD prophylaxis might further improve outcomes.

Hematopoietic Stem Cell Transplantation Activity in China 2020-2021 During the SARS-CoV-2 Pandemic: A Report From the Chinese Blood and Marrow Transplantation Registry Group

Between 2020 and 2021, 31,525 hematopoietic stem cell transplantations (HSCTs) were reported to the Chinese Blood and Marrow Transplantation Registry Group throughout mainland China. In this report, we describe the activity and current trends for HSCT in China during the SARS-CoV-2 pandemic. In 2020, a total of 13,415 cases of HSCT were reported from 166 transplantation teams, and 75% (10,042 cases) were allogeneic HSCTs. In 2021, a total of 18,110 cases of HSCT were reported from 174 transplantation teams, and 70% (12,744 cases) were allogeneic HSCTs. Haploidentical donor (HID) transplantation accounted for 63% (7977 cases) of allogeneic HSCTs in 2021. The most common indications for allogeneic HSCT for malignant disease were acute myeloid leukemia (37%) and acute lymphoblastic leukemia (23%), and the largest proportion of nonmalignant disease comprised aplastic anemia (13%). The peripheral blood stem cell source accounted for 41% of HIDs and 75% of matched sibling donors. The BuCy-based regimen (57%) was the most popular conditioning regimen for allogeneic HSCT, followed by the BuFlu-based regimen (28%) and total body irradiation-based regimen (11%). This survey provides comprehensive information about the current activities and might benefit clinical physicians' decision planning for HSCT.

Alternative Transplantation With Post-Transplantation Cyclophosphamide in Aplastic Anemia: A Retrospective Report From the BMF-WG of Hunan Province, China

Although the possibility of first-line hematopoietic cell transplantation (HCT) from alternative donors in severe aplastic anemia (SAA) patients has been suggested recently, transplantation strategies are still being investigated. We established a novel post-transplantation cyclophosphamide-based HCT protocol for patients with SAA in prior studies. We explores the effectiveness and safety of this HCT approach either as first-line or as salvage treatment in SAA patients. Outcomes of 71 consecutive young patients, who received HCT from unrelated or haploidentical donors, were retrospectively analyzed. According to their treatment before transplantation, the patients were classified into treatment-naive (TN) and relapsed or refractory (R/R) patients. The R/R patients were designated as such when a patient did not respond to previous immunosuppressive therapy or relapsed. We administered an antithymocyte globulin (ATG)-free, total body irradiation (TBI)-free conditioning regimen comprising cyclophosphamide, busulfan, and fludarabine, all in an intravenous formula. We used a thorough post-transplantation prophylaxis regimen for GVHD, including post-transplantation cyclophosphamide (PTCy) and short-term methotrexate and long-term cyclosporine A. The median age of the cohort was 16 (95% confidence interval, 12-20) years at transplantation. Most patients (61 of 71) received HCT from haploidentical donors, and the others received HCT from unrelated donors. TN patients (n = 38) were younger and had a shorter time-to-transplant and lower HCT-specific comorbidity index than patients with R/R diseases (n = 33). The frequencies of graft failure, grade II-IV acute graft-versus-host disease (GVHD), and moderate-severe chronic GVHD were similar, at 5.3% versus 6.5% (P = .057), 8.3% versus 0% (P = .109), and 5.7% versus 0% (P = .199) between R/R and TN patients. With a median 42-month follow-up, the frequencies of overall survival (OS) and event-free survival (EFS) were higher in the TN group than in the R/R group (100% versus 84.8% [P = .013] and 86.8% versus 75.8% [P = .255], respectively). All patients who achieved successful engraftment showed full donor chimerism. Four patients, all in the R/R group, suffered from donor-type aplasia; of these, 2 died, 1 was salvaged with another transplantation, and the final one was still receiving transfusion at the last follow-up. Currently, 93.9% (62 of 66) of the patients are alive more than 12 months after transplantation; of these 93.5% (58 of 62) no longer receive immunosuppression, including 91.7% (33 of 34) of the TN group and 89.3% (25 of 28) in the R/R group. This novel TBI-free and ATG-free HCT protocol using a reduced-intensity conditioning regimen followed by modified PTCy achieved promising engraftment, minimal GVHD risk, and encouraging OS and EFS. Our study suggests that unrelated or haploidentical HCT with PTCy can be used as a first-line treatment for young patients with SAA. Nevertheless, further efforts are needed to explore possibilities for older patients and patients with a poor performance status.

Comparisons of unmanipulated haploidentical donor, unrelated cord blood donor and matched unrelated donor hematopoietic stem cell transplantation in pediatric acquired severe aplastic anemia: a single center study

We retrospectively analyzed the outcomes of 240 pediatric SAA patients who underwent unmanipulated alternative HSCT between September 2012 and November 2020 at our center. The incidence of GF (PGF + SGF) was higher in the UCBD cohort compared to the MUD and HID cohorts [(13.5% ± 6.5%) vs (0%), and (1.6% ± 5.3%), respectively, p = .0001]. The incidence of platelet engraftment within 180 days post-HSCT was lower in the UCBD cohort (82.4% ± 2.3%) compared to the HID group (96.2% ± 1.3%) and the MUD group (97.4% ± 0.5%) (p = .020). the median duration time for platelet engraftment in the UCBD cohort was 29 days, longer than in HID cohort 14 days and the MUD cohort 13 days (p = .005). UCBD cohort had a lower 3-year failure-free survival (FFS) (70.5% ± 8.4%) compared to the HID cohort (81.1% ± 4.3%) and the MUD cohort (92.5% ± 3.1%) (p = .030) and lower 3-year GVHD/relapse free survival (GRFS) (63.3% ± 9.5.4%) compared to the HID cohort (75.5% ± 6.8%) and MUD cohort (87.9% ± 4.5%) (p = .002). UCBD-HSCT had inferior FFS and GRFS compared to an HSCT with an HID or MUD in pediatric patients with acquired SAA. A UCBD-HSCT had a higher GF and lower incidence of platelet engraftment and longer platelet engraftment time.

Association between haploidentical hematopoietic stem cell transplantation combined with an umbilical cord blood unit and graft-versus-host disease in pediatric patients with acquired severe aplastic anemia

Background:

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) based on granulocyte colony-stimulating factor plus anti-thymocyte regimens (‘Beijing Protocol’) provides a salvage treatment for patients of acquired severe aplastic anemia (SAA) in China. However, graft-versus-host disease (GVHD) is a major impediment of haplo-HSCT due to human leukocyte antigen disparity. Recently, haplo-HSCT combined with umbilical cord blood (UCB) (haplo-cord HSCT) is performed in clinical trials to potentially reduce the risk of severe GVHD. Nevertheless, studies comparing GVHD in pediatric patients receiving haplo and haplo-cord HSCT for SAA are limited.

Objective:

The objective of this study was to investigate the impact of UCB co-infusion on GVHD in pediatric patients receiving haplo-HSCT for SAA.

Design:

We conducted a retrospective study of 91 consecutive SAA children undergoing haploidentical transplantation based on the ‘Beijing Protocol’ with or without co-infusion of UCB in our center.

Methods:

All patients received uniform non-myeloablative conditioning and GVHD prophylaxis. We compared baseline characteristics and transplant outcomes between the haplo (n = 35) and haplo-cord (n = 56) recipients.

Results:

All 91 patients achieved hematopoietic recovery from haploidentical donors, with a higher incidence of peri-engraftment syndrome observed with the haplo-cord group as compared with the haplo group (75.0% versus 48.6%, p = 0.029). Notably, the haplo-cord group showed a lower incidence of II–IV acute GVHD (aGVHD) than the haplo group (16.1% versus 42.9%, p = 0.002). Observed incidences of chronic GVHD (cGVHD) and moderate to severe cGVHD in the haplo-cord group were also lower than that in the haplo group (25.6% versus 51.3%, p = 0.019; 16.2% versus 41.3%, p = 0.016, respectively). Haplo-cord HSCT was identified as the only factor associated with a lower incidence of II–IV aGVHD and cGVHD in multivariate analysis. However, no differences were observed between the two groups for infections and survival outcomes.

Conclusion:

Our data indicated that co-infusion of UCB in ‘Beijing Protocol’-based haplo-HSCT may be effective for reducing the risk of severe GVHD in SAA children.

The prognostic impact of previously infectious complications on allogeneic hematopoietic stem cell transplantation for patients with severe aplastic anemia: A single-center, retrospective study

Whether infections before transplantation impair the survival of patients with severe aplastic anemia (SAA) remains unclear. The aim of this retrospective cohort analysis was to compare survival between patients with SAA who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) with infection (n=66) and patients without infection (n=189) from one medical center. There were no differences in baseline characteristics, except that more patients in the infection group were diagnosed with VSAA (59.09% vs. 30.69%, P<0.001), and their grafts were more peripheral blood stem cells (89.39% vs. 76.72%, P=0.042). In addition, the percentage of patients with multidrug-resistant organism colonization or infection in the infection group was larger (16.7% vs. 0.5%, P<0.001). The median days of engraftment were similar between the two groups; however, the 28-day engraftment rates of neutrophils and platelets were lower in the infection group. No differences were observed in terms of grades II–IV acute graft-versus-host disease (aGVHD) (P=0.418), grades III–IV aGVHD (P=0.075), mild to severe chronic GVHD (cGVHD) (P=0.899), and moderate to severe cGVHD (P=0.342). Patients in the infection group had more bloodstream infections before engraftment (28.8% vs. 15.3%, P=0.016), and the primary cause of death was infection instead of aGVHD in contrast to patients without infection (16.7% vs. 4.2%, P=0.002). Finally, the estimated overall survival (OS), failure-free survival (FFS), and GVHD-free FFS at 5 years were 63% (95% CI, 51–78), 60% (95% CI, 47–74), and 55% (95% CI, 43–70) in patients with infection before transplantation versus 86% (95% CI, 81–92) (P<0.001), 82% (95% CI, 76–88) (P<0.001), and 75% (95% CI, 69–82) (P=0.003) in patients without infection before transplantation, respectively. Multivariate analysis identified haploidentical HSCT and pre-HSCT anti-infection response, defined as partial remission (PR) or stable disease (SD), as adverse factors of OS and FFS. In conclusion, our study demonstrated that SAA patients with infection defined as PR or SD but not complete remission before allo-HSCT showed inferior survival compared with patients without infection. Therefore, more attention should be paid to prophylaxis and complete control of infectious complications before transplantation among SAA patients.

Severe aplastic anemia patients with infection who received an allogeneic hematopoietic stem cell transplantation had a better chance: Long-term outcomes of a multicenter study

Background and aims

How to select the treatment is a challenge for the management of acquired patients with infections. This study aimed at comparing the outcomes of SAA with infections who had an allogeneic hematopoietic stem cell transplantation (allo-HSCT)with that of patients who had an infection and received non-HSCT therapy.

Methods

We retrospectively compared the outcomes of patients with acquired SAA and infections who had an allo-HSCT (n = 141) with that of patients who had an infection and received non-HSCT therapy (n = 186) between July 2004 and January 2020.

Results

The treatment-related mortality (TRM) of grade 1-2 infections in the HSCT and non-HSCT groups was 24.99% and 13.68%, respectively (P = 0.206), while the TRM of grade 3-4 infections was lower in the HSCT group than that observed in the non-HSCT group (18.54% vs. 33.33%, P = 0.036). At 6 months post-treatment, 91.30% patients in the HSCT group and 8.78% patients in the non-HSCT group had achieved a normal blood profile (P &lt; 0.0001). The time required to discontinue transfusions of red blood cells and platelets in the non-HSCT group was longer than in the HSCT group (P &lt; 0.0001). Estimated overall survival (OS) at 6 years was similar in the two groups (75.5% ± 3.9% vs. 76.3% ± 3.1%, P = 0.996), while the estimated failure-free survival (FFS) at 6 years was 75.2% ± 3.8% in the HSCT group and 48.9% ± 3.7% in the non-HSCT group (P &lt; 0.0001). Multivariate analysis showed that younger age, lower grade of infection (grade 1-2), and SAA (vs. very SAA) were favorable factors for OS (P &lt; 0.05), and that the choice of HSCT and younger age were favorable factors for FFS (P &lt; 0.0001).

Conclusion

These results suggest that allo-HSCT has a better chance of a successful outcome than non-HSCT in SAA patients with an infection.

Matched related transplantation versus immunosuppressive therapy plus eltrombopag for first-line treatment of severe aplastic anemia: a multicenter, prospective study

This study prospectively compared the efficacy and safety between matched related donor-hematopoietic stem cell transplantation (MRD-HSCT) (n = 108) and immunosuppressive therapy (IST) plus eltrombopag (EPAG) (IST + EPAG) (n = 104) to determine whether MRD-HSCT was still superior as a front-line treatment for patients with severe aplastic anemia (SAA). Compared with IST + EPAG group, patients in the MRD-HSCT achieved faster transfusion independence, absolute neutrophil count ≥ 1.0 × 10⁹/L (P < 0.05), as well as high percentage of normal blood routine at 6-month (86.5% vs. 23.7%, P < 0.001). In the MRD-HSCT and IST + EPAG groups, 3-year overall survival (OS) was 84.2 ± 3.5% and 89.7 ± 3.1% (P = 0.164), whereas 3-year failure-free survival (FFS) was 81.4 ± 4.0% and 59.1 ± 4.9% (P = 0.002), respectively. Subgroup analysis indicated that the FFS of the MRD-HSCT was superior to that of the IST + EPAG among patients aged < 40 years old (81.0 ± 4.6% vs. 63.7 ± 6.5%, P = 0.033), and among patients with vSAA (86.1 ± 5.9% vs. 54.9 ± 7.9%, P = 0.003), while the 3-year OS of the IST + EPAG was higher than that of the MRD-HSCT among the patient aged ≥ 40 years old (100.0 ± 0.0% vs. 77.8 ± 9.8%, P = 0.036). Multivariate analysis showed that first-line MRD-HSCT treatment was associated favorably with normal blood results at 6-month and FFS (P < 0.05). These outcomes suggest that MRD-HSCT remains the preferred first-line option for SAA patients aged < 40 years old or with vSAA even in the era of EPAG.

Comparison of Haploidentical Hematopoietic Stem Cell Transplant With or Without Unrelated Cord Blood Infusion in Severe Aplastic Anemia: Outcomes of a Multicenter Study

The purpose of this study in severe aplastic anemia (SAA) patients was to compare the feasibility and efficacy of haploidentical hematological stem cell transplantation combined with a single unrelated cord blood (UCB) infusion (Haplo-cord-HSCT) or haplo-identical HSCT (Haplo-HSCT) alone. The five-year graft-versus-host disease (GVHD)-free or failure-free survival (GFFS) was similar between the two groups (72.4 ± 3.4% vs. 65.4 ± 5.2%, P = 0.178); however, the five-year overall survival (OS) was more favorable in the Haplo-cord-HSCT group than that in the Haplo-HSCT group (84.0 ± 2.8% vs. 72.6 ± 4.9%, P = 0.022), as was transplantation-related mortality (16.4% vs. 27.4%, P = 0.039). Multivariate analysis showed that Haplo-cord HSCT was the only independent determinant of increased OS (P = 0.013). Explorative subgroup analysis showed that only an Human leukocyte antigen-A (HLA-A) allele match between UCB and the recipient was a beneficial factor for GFFS in the Haplo-cord-HSCT group (P = 0.011). In the haplo-cord with an HLA-A match (n = 139) or mismatch (n = 32) or Haplo-HSCT groups, a haplo-cord HLA-A allele match was associated with lower I–IV and III–IV acute GVHD. The haplo-cord with an HLA-A match subgroup also had higher five-year OS than the Haplo-HSCT group (85.4 ± 3.0% vs. 72.6 ± 4.9%, P = 0.013), and higher five-year GFFS than the Haplo-cord HLA-A allele mismatch subgroup (76.2 ± 3.6% vs. 56.3 ± 8.8%, P = 0.011). These findings suggest that the coinfusion of a single UCB potentially improves survival of Haplo-HSCT in SAA patients and that an HLA-A allele-matched UCB is the preferred option.

Comparable clinical outcomes of haploidentical hematopoietic stem cell transplantation in patients with hepatitis-associated aplastic anemia and non-hepatitis-associated aplastic anemia

Hepatitis-associated aplastic anemia (HAAA), a rare subtype of aplastic anemia (AA), is defined as bone marrow failure occurring after acute hepatitis. Severe HAAA requires immunosuppressive therapy (IST) or hematopoietic stem cell transplantation (HSCT) as lifesaving treatment. The outcomes of HAAA patients who underwent haploidentical hematopoietic stem cell transplantation (haplo-HSCT) have not been systematically evaluated. We retrospectively compared the characteristics of 15 patients with HAAA and 60 non-hepatitis-associated aplastic anemia (non-HAAA) patients, all 75 of whom underwent haplo-HSCT in our hospital between January 2006 and October 2021. The median ages of the patients were 18 years old (range, 3-36) for HAAA patients and 13 years (range, 2-45) for non-HAAA patients (p = 0.693). The median time for neutrophil engraftment was 14 days (range, 11-22) in the HAAA group and 12 days (range, 10-21) in the non-HAAA group (p = 0.363). At the time of analysis, 15 HAAA patients and 58 non-HAAA patients were alive, and their median follow-up times were 37 (range, 3-87) months and 31 (range, 2-110) months (p = 0.347), respectively. There were no significant differences in the three-year overall survival (OS) rates (100% vs. 96.7 ± 0.33%, P = 0.638) or liver event-free survival (LEFS) (80.0 ± 0.17% vs. 76.7 ± 0.19%, P = 0.747) between the two groups. Despite the small number of HAAA patients due to the rarity of the disease, these results, such as the similar incidence rates of 3-year OS and fewer liver events than expected, suggest that haplo-HSCT is a feasible treatment for HAAA a when there are no human leukocyte antigen (HLA)-matched donors available and has a low risk of transplant-related mortality and complications.

Comparable long-term outcomes between upfront haploidentical and identical sibling donor transplant in aplastic anemia: a national registry-based study

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a curative option for severe aplastic anemia (SAA), and transplantation from identical sibling donors (ISD) has been recommended as a first-line treatment. Haploidentical donor (HID) transplantation for SAA has made great advances; thus, an increased role of HID-SCT in SAA should be considered. We performed a national registry-based analysis comparing long-term outcomes in the upfront HID or upfront ISD SCT setting. A total of 342 SAA patients were enrolled, with 183 patients receiving HID SCT and 159 receiving ISD SCT. The estimated 9-year overall survival and failure-free survival were 87.1±2.5% and 89.3±3.7% (P=0.173) and 86.5±2.6% versus 88.1±3.8% (P=0.257) for patients in the HID and ISD SCT groups, respectively. Transplantation from HID or ISD SCT has greatly improved quality of life (QoL) levels post-HSCT compared to pre-HSCT. The occurrence of chronic graft-versus-host disease was the only identified adverse factor affecting each subscale of QoL. Physical and mental component summaries in adults as well as physical, mental, social, and role well-being in children were all similar between HID and ISD SCT at 5-year time points. At the last follow-up, the proportion of returning to society was comparable between the HID and ISD groups, showing 78.0% versus 84.6% among children and 74.6% versus 81.2% among adults. These data suggest that haploidentical transplant can be considered a potential therapeutic option in the upfront setting for SAA patients in the absence of an HLA-identical related or unrelated donor.

Long-term follow-up of haploidentical transplantation in relapsed/refractory severe aplastic anemia: a multicenter prospective study

In recent decades, haploidentical stem cell transplantation (haplo-SCT) to treat severe aplastic anemia (SAA) has achieved remarkable progress. However, long-term results are still lacking. We conducted a multicenter prospective study involving SAA patients who underwent haplo-SCT as salvage therapy. Long-term outcomes were assessed, mainly focusing on survival and quality of life (QoL). Longitudinal QoL was prospectively evaluated during pretransplantation and at 3 and 5 years posttransplantation using the SF-36 scale in adults and the PedsQL 4.0 scale in children. A total of 287 SAA patients were enrolled, and the median follow-up was 4.56 years (range, 3.01-9.05 years) among surviving patients. During the long-term follow-up, 268 of 275 evaluable patients (97.5%) obtained sustained full donor chimerism, and 93.4% had complete hematopoietic recovery. The estimated overall survival and failure-free survival for the whole cohort at 9 years were 85.4% ± 2.1% and 84.0% ± 2.2%, respectively. Age (≥18 years) and a poorer performance status (ECOG >1) were identified as risk factors for survival outcomes. For QoL recovery after haplo-SCT, we found that QoL progressively improved from pretransplantation to the 3-year and 5-year time points with statistical significance. The occurrence of chronic graft versus host disease was a risk factor predicting poorer QoL scores in both the child and adult cohorts. At the last follow-up, 74.0% of children and 72.9% of adults returned to normal school or work. These inspiring long-term outcomes suggest that salvage transplantation with haploidentical donors can be routine practice for SAA patients without human leukocyte antigen (HLA)-matched donors.

The Incidence, Outcomes, and Risk Factors of Secondary Poor Graft Function in Haploidentical Hematopoietic Stem Cell Transplantation for Acquired Aplastic Anemia

Secondary poor graft function (sPGF) increases the risk of life-threatening complications after hematopoietic stem cell transplantation (HSCT). The incidence, clinical outcomes, and risk factors of sPGF have not been elucidated in haploidentical (haplo-) HSCT for acquired aplastic anemia (AA) patients. We retrospectively reviewed 423 consecutive AA patients who underwent haplo-HSCT between January 2006 and December 2020 and report a 3-year cumulative incidence of 4.62% (95% confidence interval [CI]: 3.92%-10.23%) of sPGF. While no primary PGF occurred. The median time to sPGF was 121 days (range 30-626 days) after transplantation. To clarify the risk factors for sPGF, 17 sPGF cases and 382 without PGF were further analyzed. Compared to patients without PGF, the 2-year overall survival was significantly poorer for sPGF patients (67.7% vs 90.8%, p =.002). Twelve sPGF patients were alive until the last follow-up, and 7 achieved transfusion independency. The multivariable analyses revealed that later neutrophil engraftment (OR 2.819, p=.049) and a history of refractory cytomegalovirus viremia (OR=7.038, p=.002) post-transplantation were associated with sPGF. There was weak evidence that a history of grade 3-4 acute graft-versus-host disease increased the risk of sPGF (p=.063). We advocated better post-transplantation strategies to balance the risk of immunosuppression and viral reactivation for haplo-HSCT in AA patients.

Comparisons Between modified PTCY and G-CSF/ATG Regimens for Haploidentical Transplantation in Patients with Aplastic Anemia

BACKGROUND

Haploidentical transplantation has become an alternative treatment option for aplastic anemia patients without matched sibling donors or matched unrelated donors. Recently, the post-transplantation cyclophosphamide (PTCY) regimen and granulocyte colony-stimulating factor (G-CSF)/antithymocyte globulin (ATG) regimen have become the most common protocols used worldwide.

OBJECTIVE

We designed this retrospective study to compare the outcomes of patients receiving a modified post-transplantation cyclophosphamide (mPTCY) regimen versus the G-CSF/ATG regimen.

STUDY DESIGN

We retrospectively reviewed and analyzed the clinical data of 130 aplastic anemia patients who underwent haplo-HSCT and received the mPTCY regimen (n=55) or G-CSF/ATG regimen (n=75) between Jan 2013 and Jun 2021 across seven transplant centers.

RESULTS

Neutrophil engraftment was successful in all patients within 30 days in the G-CSF/ATG group. The cumulative neutrophil engraftment rate in the mPTCY group was 96.36% (95% CI, 94.57-97.57, P=0.010). The median time of neutrophil engraftment in the G-CSF/ATG group was 10 (7-28) days, which was more rapid than that observed in the mPTCY group (P <0.001). There were no significant differences in the incidence of graft versus host disease (GVHD) between the two groups. The cumulative incidence of II-IV acute GVHD was 18.40% (95% CI, 4.27-40.31) in the mPTCY group and 19.32% (95% CI, 5.86-38.58) in the G-CSF/ATG group, while the cumulative incidence of III-IV acute GVHD was 7.31% (95% CI, 0.09-37.48) in the mPTCY group and 7.57% (95% CI, 0.20-34.19) in the G-CSF/ATG group. Similarly, no significant difference was observed between the two groups in terms of overall survival (OS), failure-free survival (FFS), and GVHD relapse-free survival (GRFS). The 2-year OS, FFS and GRFS rates were 95.91% (95% CI, 84.59-98.96), 92.25% (95% CI, 80.59-97.03) and 86.68% (95% CI, 73.98-93.44), respectively, in the mPTCY group and 86.67% (95% CI, 76.64-92.59), 81.28% (95% CI, 70.45-88.46) and 77.20% (95% CI, 65.89-85.16), respectively, in the G-CSF/ATG group. The transplantation-related mortality (TRM) rate was significantly higher in the G-CSG/ATG group than in the mPTCY group (13.33% in the G-CSG/ATG group versus 1.96% in the mPTCY group, P=0.022). In multivariate analysis, female donors, a higher hematopoietic cell transplantation comorbidity index (HCT-CI) and III-IV aGVHD were associated with worse survival outcomes.

CONCLUSIONS

In conclusion, the mPTCY and G-CSF/ATG regimens led to similar outcomes in AA patients, but quicker engraftment was observed with the ATG/G-CSF regimen, and a lower incidence of TRM was observed with the mPTCY regimen.

Combination of Haploidentical Hematopoietic Stem Cell Transplantation with Umbilical Cord-Derived Mesenchymal Stem Cells in Patients with Severe Aplastic Anemia: a Retrospective, Controlled Study

Objective:

We retrospectively compared the outcomes of patients with severe aplastic anemia (SAA) who received haploidentical hematopoietic stem cell transplantation (haplo-HSCT) combined or not combined with umbilical cord-derived mesenchymal stem cells (UC-MSCs).

Materials and Methods:

A total of 101 patients with SAA were enrolled in this study and treated with haplo-HSCT plus UC-MSC infusion (MSC group, n=47) or haplo-HSCT alone (non-MSC group, n=54).

Results:

The median time to neutrophil engraftment in the MSC and non-MSC group was 11 (range: 8-19) and 12 (range: 8-23) days, respectively (p=0.049), with a respective cumulative incidence (CI) of 97.82% and 97.96% (p=0.101). Compared to the non-MSC group, the MSC group had a lower CI of chronic graft-versus-host disease (GVHD) (8.60±0.25% vs. 24.57±0.48%, p=0.048), but similar rates of grades II-IV acute GVHD (23.40±0.39% vs. 24.49±0.39%, p=0.849), grades III-IV acute GVHD (8.51±0.17% vs. 10.20±0.19%, p=0.765), and moderate-severe chronic GVHD (2.38±0.06% vs. 7.45±0.18%, p=0.352) were observed. The estimated 5-year overall survival (OS) rates were 78.3±6.1% and 70.1±6.3% (p=0.292) while the estimated 5-year GVHD-free, failure-free survival (GFFS) rates were 76.6±6.2% and 56.7±6.9% (p=0.045) in the MSC and non-MSC groups, respectively.

Conclusion:

In multivariate analysis, graft failure was the only adverse predictor for OS. Meanwhile, graft failure, grades III-IV acute GVHD, and moderate-severe chronic GVHD could predict worse GFFS. Our results indicated that haplo-HSCT combined with UC-MSCs infusion was an effective and safe option for SAA patients.

Comparison of Hematopoietic Stem Cell Transplantation Outcomes Using Matched Sibling Donors, Haploidentical Donors, and Immunosuppressive Therapy for Patients With Acquired Aplastic Anemia

We retrospectively compared the outcomes of 387 consecutive patients with acquired aplastic anemia (AA) who underwent hematopoietic stem cell transplantation (HSCT) with a fludarabine-based conditioning regimen from matched sibling donors (MSD) (n = 108) or haploidentical donors (HID) (n = 91) and immunosuppressive therapy (IST) (n = 188) from 2014 to 2020 at our hospital. Compared with HID-HSCT, MSD-HSCT had a lower incidence of graft failure (1% vs. 7%, p = 0.062), grade II–IV acute graft versus host disease (aGvHD) (16% vs. 35%, p = 0.001), and mild to severe chronic GvHD (cGvHD) (8% vs. 23%, p = 0.007), but an equivalent incidence of grade III–IV aGvHD (8% vs. 12%, p = 0.237) and moderate to severe cGvHD (3% vs. 9%, p = 0.076). HSCT had superior blood count recovery at 3, 6, and 12 months compared with IST (p < 0.001). The estimated 5-year overall survival (OS) of the MSD, HID, and IST groups were 86%, 72%, and 79% (p = 0.02), respectively; accordingly, the failure-free survival (FFS) rates were 85%, 68%, and 56%, respectively (p < 0.001). For patients aged ≤40 years, the OS rate was still significantly superior for MSD-HSCT receipients compared to HID-HSCT receipients (89% vs. 76%, p = 0.024) while the HID-HSCT recipients showed similar OS (76% vs. 78%, p = 0.166) but superior FFS (p = 0.047) when follow-up was longer than 14.5 months in contrast to IST. In a multivariate analysis, HID-HSCT and a conditioning regimen that included busulfan were adversely related to OS among patients who received allografts. In conclusion, MSD-HSCT was the frontline choice for patients with severe AA aged ≤40 years, while HID-HSCT was as effective as IST for patients without an MSD.

Optimal Active Anti-Thymocyte Globulin Exposure Associated with Minimum Risk of Virus Reactivation and Comparable Acute Graft-Versus-Host Disease Under Adult Myeloablative Haploidentical Peripheral Blood Stem Cell Transplantation

Anti-thymocyte globulin (ATG) is often included in the conditioning regimen to prevent graft-versus-host disease (GVHD) in allogeneic hematopoietic cell transplantation (allo-HCT). However, the risk of virus reactivation increases significantly. We conducted a single-center prospective study to identify the optimal ATG exposure that ensures engraftment, effectively prevents acute GVHD, and reduces the risk of virus reactivation without increasing relapse of malignant diseases in haploidentical peripheral blood stem cell transplantation (haplo-PBSCT). From September 2018 to June 2020, 106 patients (median age, 32 years) with malignant hematological diseases who received haplo-PBSCT for the first time were enrolled. All patients received 10 mg/kg rabbit ATG (thymoglobulin) divided for 4 days (days -5 to -2). Pre-transplant, post-transplant, and total areas under the concentration-time curve (AUCs) of active ATG were calculated. Total AUC of active ATG was shown to be the best predictor for virus reactivation and acute GVHD of grades II to IV or grades III and IV. The optimal total AUC range of active ATG was 100 to 148.5 UE/mL/day. The median time was 14 versus 13 days (P = .184) for myeloid engraftment and 13 versus 13 days (P = .263) for platelet engraftment in the optimal and non-optimal AUC groups, respectively. The optimal AUC group showed a lower cumulative incidence of cytomegalovirus (CMV) reactivation and persistent CMV viremia than the non-optimal AUC group: 60.6% (95% confidence interval [CI], 48.3%-73.1%) versus 77.1% (95% CI, 64.5%-87.7%; P = .016) and 31.5% (95% CI, 21.2%-45.3%) versus 56.3% (95% CI, 42.9%-70.4%; P = .007), respectively. The cumulative incidence of persistent Epstein-Barr virus (EBV) viremia in the optimal AUC group was significantly lower than the non-optimal total AUC group: 33.1% (95% CI, 22.5%-46.8%) versus 52.6% (95% CI, 39.3%-67.2%; P = .048). However, there was no difference in EBV reactivation (P = .752). Similar outcomes were observed for grade II to IV and grade III and IV acute GVHD between the two groups: 48.6% (95% CI, 36.8%-62.0%) versus 37.0% (95% CI, 24.8%-52.5%; P = .113) and 10.4% (95% CI, 4.8%-21.7%) versus 4.2% (95% CI, 1.0%-15.6%; P = .234, respectively. Relapse, non-relapse mortality, and disease-free survival demonstrated no significant differences between the two groups. But, overall survival at 2 years tended to increase in the optimal AUC group: 75.7% (95% CI, 62.4%-84.8%) versus 57.8% (95% CI, 42.4%-70.4%; P = .061). These data support an optimal active ATG exposure of 110 to 148.5 UE/mL/day in haplo-PBSCT. Individualized dosing of ATG in allo-HCT might reduce the risk of virus reactivation and effectively prevent acute GVHD simultaneously.

Pre-Transplant Platelet Refractoriness and Alternative Donors Are Associated With Cytomegalovirus Retinitis in Hematopoietic Stem Cell Transplantation for Severe Aplastic Anemia

Background

Cytomegalovirus retinitis is a severe, vision-threatening opportunistic infection in an immunodeficient population. Reports on cytomegalovirus retinitis in hematopoietic stem cell transplant recipients due to severe aplastic anemia have been scant. This study assessed the risk of cytomegalovirus retinitis in relation to the pre-transplant status of severe aplastic anemia patients.

Methods

We conducted a retrospective nested case-control study of cytomegalovirus retinitis among severe aplastic anemia patients receiving allogeneic hematopoietic stem cell transplants in a tertiary care institution that attends severe aplastic anemia patients from southern China from January 1, 2013 to December 31, 2018. Each cytomegalovirus retinitis case was matched with four controls without cytomegalovirus retinitis by age and gender. Thirteen pre-transplant parameters were chosen to compare the risk factor levels between the cases and controls. Multivariable logistic regressions were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs).

Results

A total of 361 severe aplastic anemia patients received hematopoietic stem cell transplants in the study period 2013–2018 in our medical institution, and 31 (8.58%) developed cytomegalovirus retinitis. Cytomegalovirus retinitis was diagnosed in the median of 148 days after transplantation. We confirmed platelet refractoriness more frequently in cases than in controls (p = 0.0005). Compared with human leukocyte antigen-matched sibling donors, alternative donors were significantly more prone to cytomegalovirus retinitis (p = 0.0009). After stepwise selection in multivariate logistic regression, platelet refractoriness (OR 5.41, 95% CI 1.98–15.39), haploidentical donor (OR 7.46, 95% CI 2.19–34.87), and unrelated donor (OR 8.38, 95% CI 2.30–41.34) were associated with an increased risk of cytomegalovirus retinitis.

Conclusions

Pre-transplant platelet refractoriness and alternative donors were significant predictors of cytomegalovirus retinitis in severe aplastic anemia recipients. These results highlight the importance of accounting for existing risks while developing prevention strategies and preemptive treatment for severe aplastic anemia recipients. We recommend that the platelet count be closely monitored and thrombopoietin be properly applied during the period when cytomegalovirus retinitis is prone to occur.

Comparison of porcine ALG and rabbit ATG on outcomes of HLA-haploidentical hematopoietic stem cell transplantation for patients with acquired aplastic anemia

Objective

To evaluate the efficacy and safety of P-ALG (porcine anti-lymphocyte globulin) and R-ATG (rabbit anti-thymocyte globulin) in the conditioning regime for patients with acquired aplastic anemia who underwent HLA-haploidentical hematopoietic stem cell transplantation (halpo-HSCT).

Methods

A total of 91 patients with acquired aplastic anemia who received haplo-HSCT at our center between January 2014 and December 2020 were retrospectively reviewed. Twenty-eight patients were in the P-ALG group while sixty-three patients were in the R-ATG group.

Results

The median time was 11 versus 13 days (P = 0.294) for myeloid engraftment and 12.5 versus 15 days (P = 0.465) for platelet engraftment in the P-ALG and R-ATG groups, respectively. There were no significant difference in 5-year overall survival (74.83% ± 8.24% vs 72.29% ± 6.26%, P = 0.830), GVHD-free, failure-free survival (71.05% ± 8.65% vs 62.71% ± 6.22%, P = 0.662), failure-free survival (74.83% ± 8.24% vs 66.09% ± 5.84%, P = 0.647) and transplantation-related mortality (25.17% ± 8.24% vs 26.29% ± 6.22%, P = 0.708) between the two groups. The incidence of aGVHD (acute graft versus host disease) (65.39% ± 9.33% vs 62.71% ± 6.30%, P = 0.653), II–IV aGVHD (38.46% ± 9.54% vs 35.64% ± 6.24%, P = 0.695), III–IV aGVHD (19.23% ± 7.73% vs 10.53% ± 4.07%, P = 0.291), cGVHD (chronic graft versus host disease) (22.22% ± 12.25% vs 22.31% ± 6.30%, P = 0.915), and moderate to severe cGVHD (5.56% ± 5.40% vs 9.28% ± 4.46%, P = 0.993) were not significantly different. Similar outcomes were observed between the P-ALG and R-ATG groups for severe bacterial infection (17.9% vs 25.4%, P = 0.431), invasive fungal diseases (3.6% vs 9.5%, P = 0.577) and graft rejection (0% vs 9.5%, P = 0.218). However, the incidence of cytomegalovirus infection and Epstein-Barr virus infection was significantly lower in the P-ALG group (46.4% vs 71.4%, P = 0.022; 3.6% vs 25.4%, P = 0.014).

Conclusion

The efficacy and safety of P-ALG were similar with R-ATG in the setting of haplo-HSCT for patients with acquired aplastic anemia patients. P-ALG could be an alternative for R-ATG.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02410-z.

KIR in Allogeneic Hematopoietic Stem Cell Transplantation: Need for a Unified Paradigm for Donor Selection

Allogeneic hematopoietic stem cell transplantation (aHSCT) is a lifesaving therapy for hematological malignancies. For years, a fully matched HLA donor was a requisite for the procedure. However, new immunosuppressive strategies have enabled the recruitment of viable alternative donors, particularly haploidentical donors. Over 95% of patients have at least two potential haploidentical donors available to them. To identify the best haploidentical donor, the assessment of new immunogenetic criteria could help. To this end, the clinical benefit of KIR genotyping in aHSCT has been widely studied but remains contentious. This review aims to evaluate the importance of KIR-driven NK cell alloreactivity in the context of aHSCT and explain potential reasons for the discrepancies in the literature. Here, through a non-systematic review, we highlight how the studies in this field and their respective predictive models or scoring strategies could be conceptually opposed, explaining why the role of NK cells remains unclear in aHCST outcomes. We evaluate the limitations of each published prediction model and describe how every scoring strategy to date only partly delivers the requirements for optimally effective NK cells in aHSCT. Finally, we propose approaches toward finding the optimal use of KIR genotyping in aHSCT for a unified criterion for donor selection.

Comparable Outcomes in Acquired Severe Aplastic Anemia Patients With Haploidentical Donor or Matched Related Donor Transplantation: A Retrospective Single-Center Experience

Clinical data of patients with severe aplastic anemia (SAA) were retrospectively analyzed to evaluate the outcomes of haploidentical hematopoietic stem cell transplantation (HID-HSCT) with matched related sibling hematopoietic stem cell transplantation (MSD-HSCT) in complications and survivals. Thirty consecutive patients were enrolled in the study with a median follow-up of 50 months (range 4, 141), and the median age of the patients was 21 years (range 3, 49). All the patients achieved myeloid engraftment in the two cohorts. The cumulative incidences of platelet engraftment were 95.5 and 100% in HID cohort and MSD cohort, respectively. The median time for neutrophil and platelet recovery was 11 (range 9, 19) and 15 (range 10, 25) days in HID cohort, and 12 (range 10, 19) and 14 (range 8, 25) days in MSD cohort. The cumulative incidences of grade II–IV and grade III–IV acute graft vs. host disease (aGvHD) in HID cohort and in MSD cohort were 18.9 vs. 14.3% (p = 0.77) and 10.5 vs. 0% (p = 0.42), respectively. The cumulative incidences of chronic graft vs. host disease (cGvHD) was 22.7% in HID cohort and 25.5% in MSD cohort (p = 0.868). The 5-year overall survival (OS) rates and 5-year failure-free survival (FFS) rates in HID cohort and MSD cohort were 85.1 vs. 87.5% (p = 0.858), 80.3 vs. 87.5% (p = 0.635), respectively. The median time to achieve engraftment, cumulative incidence of aGvHD and cGvHD, and the 5-year OS and FFS rates were not significantly different between the two cohorts. We suggest that HID-HSCT might be a safety and effective option for SAA patients without a matched donor.

Comparable Outcomes and Health-Related Quality of Life for Severe Aplastic Anemia: Haploidentical Combined With a Single Cord Blood Unit vs Matched Related Transplants

We retrospectively compared the outcomes and health-related quality of life (HRQoL) of severe aplastic anemia (SAA) patients who received haploidentical hematopoietic stem cell transplantation with a single unrelated cord blood unit (Haplo-cord HSCT) (n = 180) or matched related donor (MRD)-HSCT (n = 128). After propensity score matching, we were able to match 88 patients in each group and to compare the outcomes between the two matched-pair groups. Haplo-cord recipients exhibited a longer median days for neutrophil engraftment (12 vs 11, P = 0.001) and for platelet engraftment (15 vs 13, P = 0.003). Haplo-cord recipients a high cumulative incidence of grades II–IV acute graft-versus-host disease (GVHD) (29.8 vs 14.0%, P = 0.006), while similar III–IV acute GVHD, total chronic GVHD, and moderate to severe chronic GVHD at four-year (all P < 0.05). Among the Haplo-cord HSCT and MRD-HSCT groups, the four-year GVHD-free/failure-free survival rates were 73.5% and 66.9% (P = 0.388) respectively, and the overall survival rates were 81.5% and 77.2% (P = 0.484), respectively. Similar comparable results also were observed between the corresponding first-line, older or younger than 40 years old subgroups. The Haplo-cord HSCT group exhibited higher scores in the physical component summary, physical functioning, general health and social functioning than the MRD-HSCT group (all P < 0.05). In the multivariate analysis, young age and Haplo-cord HSCT were favorable factors for HRQoL, while moderate to severe cGVHD was associated with lower HRQoL. These results suggest that for SAA patients, Haplo-cord HSCT could achieve at least comparable efficacy and HRQoL to MRD-HSCT.

Unmanipulated haploidentical donor and matched unrelated donor hematopoietic stem cell transplantation in patients with paroxysmal nocturnal hemoglobinuria: a single-center study

We analyzed the outcomes of 32 patients with paroxysmal nocturnal hemoglobinuria (PNH) who underwent either a haploidentical donor (HID) or a matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT). Seventeen patients received an HSCT from an HID and 15 patients received an HSCT from an MUD. The median follow-up time of the surviving patients was 36 months (range: 12-96 months). No significant differences were observed in the 3-year overall survival (OS) between the HID and MUD cohorts (74.1%±11.4% vs. 93.3%±6.4%, respectively, p=.222) or in the 3-year failure-free survival (68.8%±11.8% vs. 86.7%±8.8%, respectively, p=.307). Treatment-related mortality occurred in five patients. A univariate analysis of risk factors revealed platelet engraftment failure negatively impacted OS and FFS. We conclude that HID and MUD-HSCT are feasible and can be effective options for those PNH patients with concomitant bone marrow failure, recurrent life-threatening thrombosis, and uncontrollable hemolysis.